Polymerization of rosin



Patented Aug. '5, 1947 UNITED STATES PATENT OFFICE Burt L. Hampton, Jacksonville, Fla, assignor, by mesne assignments, to The Glidden Company, Cleveland, hio, a corporation of Ohio No Drawing. Application June 10, 1946, Serial No. 675,831

14 Claims. 1

The present invention relates to processes for the polymerization of rosin.

Polymerized rosin and its useful derivatives have many advantageous properties over ordinary unpolymerized rosin and its derivatives, such as higher melting points, higher viscosity, greater stability toward oxidation, and many others. .The use of zinc chlorides or stannic chlorides as catalyst for the polymerization has been previously proposed but the catalyst is either left in the product or numerous washings are required for its removal. United States Patent 2,247,399 describes the use of zinc chlorides as a catalyst for the polymerization, but for practical commercial operation at least 1 of the catalyst is required.

I have discovered that other metal halides described hereinafter are effective as polymerization catalysts and that by activating these halides with certain free hydrohalogen acids, smaller amounts of the halides may be employed, and the washing difliculties of prior processes may be minimized.

It is accordingly an object of the present invention to provide a new process for producingpolymerized rosin.

An additional object is to provide processes for polymerizing rosin which employ new catalysts activated or not by means of free acid.

Another object is to provide a process for polymerizing rosin whereby the halide catalyst employed may be readily removed by washing.

A further object is to provide an improved process for polymerizing rosin, in which the amount of metal halide employed as catalyst during polymerization is lowered.

Other objects will be apparent to those skilled in the art from the following description.

In the course of my experimental research in the polymerization of rosin, I have found that the mercury chlorides and bromides in both valences are eifective polymerization catalysts for gum and wood rosins. The amount of such halide catalyst which is employed may range from about 0.5% to about based on the weight of rosin present, whether as rosin per se or as rosin dissolved in a suitable solvent. The preferred limits, however, are from about 1% to 5%.

I have also found that when the above mentioned mercury halides are activated by the presence of either free hydrochloric or hydrobromic acid, smaller amounts of catalyst may be used with equal effectiveness. Under such conditions, amounts of the mercury salts as small as .01% are effective and for most purposes amounts less tween about 0.3% and 0.7% being Q preferred. Concentrations of catalyst between 1% and 10% may be used with activating acids, but the disadvantages of added cost and greater washing difliculties resulting from the use of the larger amounts of catalyst are not sufficiently offset by the benefits. Only small amounts of free acid are needed to effect the activation, but amounts greater-than a mere trace should be provided to ensure continued effectiveness throughout the duration of the polymerization treatment. For most purposes initial concentrations of free acid between about .2% and .5% provide an adequate excess but under less favorable conditions such as those of prolonged treatment greater initial concentrations of around 2% and 3%, or even up to5% may be needed. It is within the ability of one skilled in the art to determine the desired concentrations under his selected working conditions, in accordance with the foregoing indications. It should be recognized, however, that the free acid should be kept sufficiently low to avoid undesirable degradation of the material being treated, or of the final product.

The mercury chlorides or bromides may be generated in situ, if preferred, instead of employing the halide salts per se. This can be accomplished conveniently by reacting a mercurousor mercuric compound such as the oxide, hydroxide, carbonate, fluoride or iodide with hydrochloric or hydrobromlc acid. When the activating effects of free acid are desired, the in-situ production of the catalysts should be accomplished by ern ploying enough of the said acids or acid-producing materials to convert all of the compounds to the corresponding halides, and to providesome free acid in addition. Because of their greater stability, the mercuric compounds and salts are preferred.

The acid employed for activation of the catalysts, of for their in-situ production, maybe introduced as the hydrogen halide compound or it may be enerated in-situ by using materials which produce hydrochloric or hydrobromic acid under the conditions of treatment. Hydrogen chlorideproducing compounds and hydrogen bromideproducing compounds are well known to those skilled in the art, but for purposes of example, the following materials are mentioned: chlorine, phosphorous chlorides, phosphorous bromides, benzoyl chloride, acetyl chloride, and other organic acid chlorides or bromides. The reactions which are involved in producing free hydrogen halides from these and like materials are well than about 1% are satisfactory with amounts be- 6| understood. Reference may be made, however,

1 be more resistant to An Outline of Organic Chemistry by Degering, published in 1941 (4th edition) where'typical reactions with aliphatic and aromatic compounds are explained on pages 37 and 185-187 respectively.

While the polymerization, either with or without activating acid, may be carried. out on themolten rosin, it is referable to carry it out on rosin dissolved in an inert solvent. Suitable solvents are glacial acetic acid, mineral spirits, benzene, toluene, xylene, chlorc-benzene, ethylene chloride, and many other liquids known already to those skilled in the art. Various concentrations of rosin in solvent from about 30% to 100% have been employed with success, and of these,

a solution of about 80% rosin has been found tobe the most desirable from practical considerations.

Rosin generally contains some oxidized products and upon addition of the hydrohalogen acid or of the hydrogenhalide-producing material, small quantities of water are formed. Likewise, when a mercury oxide is employedas catalyst, water is formed by reaction between it and the hydrohalogen acid. The removal irom the rosin or rosin solution of water from such sources is not essential to effect polymerization, but for producing the more. highly polymerized materials it is advantageous to remove such water as well as any water present as such in the rosin or rosin solution. I

According to a preferred procedure, a solution .of rosin is first formed in an inert solvent. A small quantity of mercuricchloride or bromide or of ancxide of mercury is then added. Chlorine, hydrogen chloride, or; a material which yields H01 is next added in a quantity suiilcient to produce some free H01. Thesolution is then heated to the desired temperature, which preferably is around the boiling point of the solution but which may be any temperature between about 50 C. and

165 0., and isheated for a predetermined time between about /g hour and 100 hours to produce the desired degree of polymerization. The concentration of solvent in the mass is then adjusted (if necessary to facilitate washing) and the solutionis washed with water. In case the polymerization is carried out on molten rosin, treating temperatures ranging from the melting point to about 165 0. may be employed, and after the treatment is completed the polymerized resin should be dissolved in solvent for washing, and then washed. Ineither case the washed solution is next distilled or otherwise treated to separate the solvent. After such distillation or separation, the p'roductis characterized by the presence of loosely combined H01. The product would present disadvantages in manufacturing various other products therefrom-such as ester gum, etc., in which heating to elevated temperatures is employed. It is therefore desirable to remove the loosely combined H01. This can be done by bring- The following examples are illustrative of the invention:

Example 1 400 parts of WG-gum rosin M. P. 76 0.; A. N. 167 from which the metals have been removed by an acid wash of the original gum was dissolved in 100 parts of acetic acid and 1.2 parts of finely powdered HgClz together with 4 parts of acetyl chloride were added. The solution was gently refluxed for 6 hours and then poured into hot mineral spirits, washed with dilute HCl and twice with water. The solvent was removed with steam.

the final temperature of the resin being 200 C.

R. & B. M. P. 86 0.; acid number 166, grade H-I.

Example 2 400 parts of metal free K gum rosin of M. P. 83 0., A. N. 169 was dissolved in 100 parts of mineral spirits and 2 parts of HgCh together with 2 parts of chlorine were added and the solution heated at 140-150 0. for 5 hours. After dilutin with solvent the solution was washed three times with hot water. The mineral spirits was removed ing the polymerized rosin to temperatures oi the order 0 250 0. to 340 0., and sparging the heated rosin by passing in steam or other inert gas or vapor to sweep out the liberated H01. Bromine, hydrogen bromide, or a material which yields I-IBr may be used in place of the corresponding chlorine materials, and in the same way.

The product after removal of all of the H01 or HBr will be found to havea higher melting point and a higher viscosity in solution, and to rosin.

to oxidation than the original with steam the final temperature of the resin being 220 0. grade H, M. P. 87 0., A. N. 1'70.

Example 3 400 parts of metal free K gum rosin of M. F. 83 0., A. N. 169 was dissolved in parts of acetic acid and 2 parts of HgCh together with 2 parts of chlorine were added to the solution which was then heated at -135 0. for 5 hours. After pouring into mineral spirits the solution was washed three times, with hot water. The solvent was removed with steam, the final temperature of the resin being 220 0., grade I, R. 8: B. M. P.

89 0., A. N. 1'70. A sample of this resin was heattreated with gentle steaming at 270-280 0. for 1 hour. Grade K-M, R, 8: B. M. P. 885 C., A. N.

Example 4 400 parts of the rosin used in Example 3 was dissolved in 100 parts of acetic acid and 12 parts 01' HgCl: added. The solution was heated at -135" 0. for 6 hours, poured into mineral spirits and washed four times with hot water. The solvent was removed with steam, the final temperature of the resin being 220 0., grade I, R. 8: B. M. P. 919 0., A. N. 170.

Blank 1 Blank 2 500 parts of metal free K gum rosin of M. P. 84 0., A. N. 169 was dissolved ln'125 parts of mineral spirits and 2.5 parts of 01; added. The solution was heated at -150 0. for 5 hours, diluted with solvent and washed three times with hot water. The solvent was removed with steam, the final temperature of the resin being 220 0., grade H, M. P. 83 0., A. N. 170.

From a comparison of these Blanks with the preceding examples, it is seen that in the absence no polymerizationiseffentedz i From the foregoing examples andexplanations,

it will be recognized that 'the -invention;inits broadest aspects relates to the polymerizatiomof "rosin in liquid phase, either-as molten rosin or as a solution of rosini'n. a. suitable inert. solvent. by means of a mercury chloride or bromide as a'polymerization catalyst. In a more limited aspect the efiectiveness of the catalysts is preferably enhanced by the presence, during polymerization, of free hydrohalogen acid. While the mercury chloe ride or bromide may be employed as such, either or both may be generated in situ by reaction of an oxidic mercury compound with hydrogen chloride or hydrogen bromide, or by reaction of mercury iodide or mercury fluoride with either of the acids. In each aspect of the invention the hydrohalogen acid which is employed may be introduced as such, or it too may be formed in situ by employing a halogen-containing material which produces the desired hydrohalogen acid under the conditions of treatment.

It will be recognized that the invention also contemplates the treatment of the polymerized rosin (as produced by any of the forms of the invention just described above), by a washing step the purpose of which is to remove the catalyst, by a treating step which separates the polymerized rosin from any solvent which may have been employed during the polymerization process or washing step, and by a sparging step having the function of removing any looselycombined hydrohalide remaining .in the polymerized rosin after the washing and solvent-separating steps.

The polymerization step eifected by the use of the herein disclosed catalysts, activated or not by free acids, may be carried out at the indicated temperatures for periods of time extending from about hour to about 100 hours, or for sufiicient time to effect polymerization of at least a part of the rosin. Considerable polymerization, as indicated by the higher melting points of the products of the treatment shown in the examples, can be accomplished in a matter of a few hours, and for most purposes a treatment lasting from about hour to about 30 hours is adequate to accomplish commercially desirable results.

Having described the invention, what is claimed 1s:

1. The process for polymerizing rosin which comprises the step of treating rosin in liquid.

phase with a small amount to about 10% of a catalytic material selected from the group consisting of the mercury chlorides and mercury bromides, for a time of between about one-half hour and about 100 hours, at temperatures between about 50 C. and 165 C.

2. The process for polymerizing rosin which comprises the step of treating rosin in liquid phase with a small amount to about 10% of a catalytic material selected from the group consisting of the mercury chlorides and mercury bromides, for a time of between about one-half hour and about 100 hours, at temperatures between about 50 C. and 165 C., said catalytic material being formed in situ by reaction of a mercury-containing compound selected from the group consisting of the mercury oxides, mercury hydroxides, mercury carbonates, mercury iodides, and mercury fluorides, with a hydrohalide selected from the group consisting othydrogen chloride and hydrogen bromide.

- 3. The process of claim 2, wherein said hydrocatalytic material selected from the group consisting of the -mer'cury' chlorides and mercury bromides, for a time of between about one-half hour and'about hours, at temperatures between about 50 C. and C., said catalytic material being formed in situ by reaction of a, mercury containing compound selected from the group consisting of the mercury oxides, mercury hydroxides, mercury carbonates, mercury iodides, and mercury fluorides, with a halogen-containing substance capable of yielding under the conditions of treatment a hydrohalide selected from the group consisting of hydrogen hydrogen bromide. 5. The process of claim 4, wherein said halogen-containing material is in excess of the amount required to effect a stoichiometric reaction between said hydrohalide and said mercurycontaining compound.

6. The process for polymerizing rosin which comprisesthe step of treating rosin in liquid phase with a. small amount to about 10% of a catalytic material selected from the group consisting of the mercury chlorides and mercury bromides, in combination with a small amount of a free hydrohalide selected from the group con-' sisting of hydrogen chloride and hydrogen bromide, said treating step being carried on at temperatures between about 50 C. and 165 C. for a time sufficient to effect polymerization of at least apart of the rosin.

7. The process for polymerizing rosin which comprises the step of treating resin in liquid phase with from .01% to about 1% of a catalytic material selected from the group consisting of the mercury chlorides and mercury bromides, in combination-with a small amount of free hydrohalide cover the polymerized rosin, and sparging thev polymerized rosin at temperatures between about 250 C. and 340 C. with an inert gas to remove loosely combined hydrohalide from said polymerized rosin.

10. The process of claim 7 wherein said catalytic material is used in amounts of between about 0.3% and 0.7%.

11. The process of claim '7 wherein said free hydrohalide is obtained in situ from a halogencontaining substance capable of yielding the said hydrohalide under the conditions of treatment.

12. The process as claimed in claim 1 wherein from about 1% to 5% of said catalytic materials is employed.

13. The process for polymerizmg rosin which comprises the steps of treating molten rosin with from .01% to about 1% of a catalytic material chloride and selected from the group consisting of the mercury chlorides and mercury bromides, in combination with a small amount of tree hwdrohalide selected from thegroup consisting of hydrogen chloride and hydrogen bromide, said treatment being carried on at temperatures between the melting point of the rosin and about 165 C. fora time suflicient to effect polymerizationof at least a part of said rosin; thereafter dissolving the treated rosin in solvent to form a washable solution; washing the i0 rosin solution separating the solvent from said washed solution to recover the treated rosin; and sparging the recovered rosin at temperatures between about 250 C.'and 340 C. with inert gas to remove loosely-combined hydrohalide therefrom.

,14. The process as claimed in claim 13 wherein from about 0.3% to 0.7% of said catalytic materiai is employed;

' BURT L. HAMPTON. 

